. Update the Copyright year (only) when changing content.
. /////////////////////////////////////////////////////////////////////////////
-.set previousversion "4.85"
+.set previousversion "4.86"
.include ./local_params
.set ACL "access control lists (ACLs)"
.set I " "
.macro copyyear
-2014
+2015
.endmacro
. /////////////////////////////////////////////////////////////////////////////
waiting for it by the time it recovers, and sending them in a single SMTP
connection is clearly beneficial. Whenever a delivery to a remote host is
deferred,
-.cindex "hints database"
+.cindex "hints database" "deferred deliveries"
Exim makes a note in its hints database, and whenever a successful
SMTP delivery has happened, it looks to see if any other messages are waiting
for the same host. If any are found, they are sent over the same SMTP
defined. AAAA records (analogous to A records for IPv4) are in use, and are
currently seen as the mainstream. Another record type called A6 was proposed
as better than AAAA because it had more flexibility. However, it was felt to be
-over-complex, and its status was reduced to &"experimental"&. Exim used to
+over-complex, and its status was reduced to &"experimental"&.
+Exim used to
have a compile option for including A6 record support but this has now been
withdrawn.
.cindex "symbolic link" "to source files"
Symbolic links to relevant source files are installed in the build directory.
-&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
-building process fails if it is set.
-
If this is the first time &'make'& has been run, it calls a script that builds
a make file inside the build directory, using the configuration files from the
&_Local_& directory. The new make file is then passed to another instance of
.code
mysql_servers = <value not displayable>
.endd
-If &%configure_file%& is given as an argument, the name of the run time
-configuration file is output.
+If &%config%& is given as an argument, the config is
+output, as it was parsed, any include file resolved, any comment removed.
+
+If &%config_file%& is given as an argument, the name of the run time
+configuration file is output. (&%configure_file%& works too, for
+backward compatibility.)
If a list of configuration files was supplied, the value that is output here
is the name of the file that was actually used.
by Exim in conjunction with the &%-MC%& option. It signifies that the
connection to the remote host has been authenticated.
-.new
.vitem &%-MCD%&
.oindex "&%-MCD%&"
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option. It signifies that the
remote host supports the ESMTP &_DSN_& extension.
-.wen
.vitem &%-MCP%&
.oindex "&%-MCP%&"
Exim's configuration file is divided into a number of different parts. General
option settings must always appear at the start of the file. The other parts
are all optional, and may appear in any order. Each part other than the first
-is introduced by the word &"begin"& followed by the name of the part. The
-optional parts are:
+is introduced by the word &"begin"& followed by at least one literal
+space, and the name of the part. The optional parts are:
.ilist
&'ACL'&: Access control lists for controlling incoming SMTP mail (see chapter
message_size_limit = 100M
.endif
.endd
-sets a message size limit of 50M if the macro &`AAA`& is defined, and 100M
+sets a message size limit of 50M if the macro &`AAA`& is defined
+(or &`A`& or &`AA`&), and 100M
otherwise. If there is more than one macro named on the line, the condition
is true if any of them are defined. That is, it is an &"or"& condition. To
obtain an &"and"& condition, you need to use nested &`.ifdef`&s.
colon in the example above is necessary. If it were not there, the list would
be interpreted as the two items 127.0.0.1:: and 1.
-.section "Changing list separators" "SECID53"
+.section "Changing list separators" "SECTlistsepchange"
.cindex "list separator" "changing"
.cindex "IPv6" "addresses in lists"
Doubling colons in IPv6 addresses is an unwelcome chore, so a mechanism was
show how you can specify hosts that are permitted to send unqualified sender
and recipient addresses, respectively.
+The &%log_selector%& option is used to increase the detail of logging
+over the default:
+.code
+log_selector = +smtp_protocol_error +smtp_syntax_error \
+ +tls_certificate_verified
+.endd
+
The &%percent_hack_domains%& option is also commented out:
.code
# percent_hack_domains =
.endd
This transport is used for handling deliveries to pipes that are generated by
redirection (aliasing or users' &_.forward_& files). The &%return_output%&
-option specifies that any output generated by the pipe is to be returned to the
-sender.
+option specifies that any output on stdout or stderr generated by the pipe is to
+be returned to the sender.
.code
address_file:
driver = appendfile
lookup. Lookups of this type are conditional expansion items. Different results
can be defined for the cases of lookup success and failure. See chapter
&<<CHAPexpand>>&, where string expansions are described in detail.
+The key for the lookup is specified as part of the string expansion.
.next
Lists of domains, hosts, and email addresses can contain lookup requests as a
way of avoiding excessively long linear lists. In this case, the data that is
returned by the lookup is often (but not always) discarded; whether the lookup
succeeds or fails is what really counts. These kinds of list are described in
chapter &<<CHAPdomhosaddlists>>&.
+The key for the lookup is given by the context in which the list is expanded.
.endlist
String expansions, lists, and lookups interact with each other in such a way
&`fail`& keyword causes a &'forced expansion failure'& &-- see section
&<<SECTforexpfai>>& for an explanation of what this means.
-The supported DNS record types are A, CNAME, MX, NS, PTR, SPF, SRV, TLSA and TXT,
-and, when Exim is compiled with IPv6 support, AAAA.
-If no type is given, TXT is assumed. When the type is PTR,
-the data can be an IP address, written as normal; inversion and the addition of
-&%in-addr.arpa%& or &%ip6.arpa%& happens automatically. For example:
-.code
-${lookup dnsdb{ptr=192.168.4.5}{$value}fail}
-.endd
-If the data for a PTR record is not a syntactically valid IP address, it is not
-altered and nothing is added.
+The supported DNS record types are A, CNAME, MX, NS, PTR, SOA, SPF, SRV, TLSA
+and TXT, and, when Exim is compiled with IPv6 support, AAAA.
+If no type is given, TXT is assumed.
For any record type, if multiple records are found, the data is returned as a
concatenation, with newline as the default separator. The order, of course,
.endd
It is permitted to specify a space as the separator character. Further
white space is ignored.
+For lookup types that return multiple fields per record,
+an alternate field separator can be specified using a comma after the main
+separator character, followed immediately by the field separator.
+
+.cindex "PTR record" "in &(dnsdb)& lookup"
+When the type is PTR,
+the data can be an IP address, written as normal; inversion and the addition of
+&%in-addr.arpa%& or &%ip6.arpa%& happens automatically. For example:
+.code
+${lookup dnsdb{ptr=192.168.4.5}{$value}fail}
+.endd
+If the data for a PTR record is not a syntactically valid IP address, it is not
+altered and nothing is added.
.cindex "MX record" "in &(dnsdb)& lookup"
.cindex "SRV record" "in &(dnsdb)& lookup"
For an MX lookup, both the preference value and the host name are returned for
each record, separated by a space. For an SRV lookup, the priority, weight,
port, and host name are returned for each record, separated by spaces.
-An alternate field separator can be specified using a comma after the main
-separator character, followed immediately by the field separator.
+The field separator can be modified as above.
.cindex "TXT record" "in &(dnsdb)& lookup"
.cindex "SPF record" "in &(dnsdb)& lookup"
For TXT records with multiple items of data, only the first item is returned,
-unless a separator for them is specified using a comma after the separator
-character followed immediately by the TXT record item separator. To concatenate
-items without a separator, use a semicolon instead. For SPF records the
+unless a field separator is specified.
+To concatenate items without a separator, use a semicolon instead.
+For SPF records the
default behaviour is to concatenate multiple items without using a separator.
.code
${lookup dnsdb{>\n,: txt=a.b.example}}
It is permitted to specify a space as the separator character. Further
white space is ignored.
+.cindex "SOA record" "in &(dnsdb)& lookup"
+For an SOA lookup, while no result is obtained the lookup is redone with
+successively more leading components dropped from the given domain.
+Only the primary-nameserver field is returned unless a field separator is
+specified.
+.code
+${lookup dnsdb{>:,; soa=a.b.example.com}}
+.endd
+
.section "Dnsdb lookup modifiers" "SECTdnsdb_mod"
.cindex "dnsdb modifiers"
.cindex "modifiers" "dnsdb"
.cindex "options" "dnsdb"
-Modifiers for &(dnsdb)& lookups are givien by optional keywords,
+Modifiers for &(dnsdb)& lookups are given by optional keywords,
each followed by a comma,
that may appear before the record type.
See also the &$lookup_dnssec_authenticated$& variable.
+.cindex timeout "dns lookup"
+.cindex "DNS" timeout
+Timeout for the dnsdb lookup can be controlled by a retrans modifier.
+The form is &"retrans_VAL"& where VAL is an Exim time specification
+(e.g. &"5s"&).
+The default value is set by the main configuration option &%dns_retrans%&.
+
+Retries for the dnsdb lookup can be controlled by a retry modifier.
+The form if &"retry_VAL"& where VAL is an integer.
+The default count is set by the main configuration option &%dns_retry%&.
+
+.new
+.cindex cacheing "of dns lookup"
+.cindex TTL "of dns lookup"
+.cindex DNS TTL
+Dnsdb lookup results are cached within a single process (and its children).
+The cache entry lifetime is limited to the smallest time-to-live (TTL)
+value of the set of returned DNS records.
+.wen
+
.section "Pseudo dnsdb record types" "SECID66"
.cindex "MX record" "in &(dnsdb)& lookup"
set a server-side limit on the time taken to complete a search.
The SERVERS parameter allows you to specify an alternate list of ldap servers
-to use for an individual lookup. The global ldap_servers option provides a
+to use for an individual lookup. The global &%ldap_default_servers%& option provides a
default list of ldap servers, and a single lookup can specify a single ldap
server to use. But when you need to do a lookup with a list of servers that is
different than the default list (maybe different order, maybe a completely
found, but that is still a successful query. In other words, the list of
servers provides a backup facility, not a list of different places to look.
+.new
The &%quote_mysql%&, &%quote_pgsql%&, and &%quote_oracle%& expansion operators
convert newline, tab, carriage return, and backspace to \n, \t, \r, and \b
respectively, and the characters single-quote, double-quote, and backslash
-itself are escaped with backslashes. The &%quote_pgsql%& expansion operator, in
-addition, escapes the percent and underscore characters. This cannot be done
-for MySQL because these escapes are not recognized in contexts where these
-characters are not special.
+itself are escaped with backslashes.
+.wen
.section "Specifying the server in the query" "SECTspeserque"
For MySQL and PostgreSQL lookups (but not currently for Oracle and InterBase),
.section "Special MySQL features" "SECID73"
For MySQL, an empty host name or the use of &"localhost"& in &%mysql_servers%&
causes a connection to the server on the local host by means of a Unix domain
-socket. An alternate socket can be specified in parentheses. The full syntax of
-each item in &%mysql_servers%& is:
+socket. An alternate socket can be specified in parentheses.
+.new
+An option group name for MySQL option files can be specified in square brackets;
+the default value is &"exim"&.
+.wen
+The full syntax of each item in &%mysql_servers%& is:
.display
-<&'hostname'&>::<&'port'&>(<&'socket name'&>)/<&'database'&>/&&&
- <&'user'&>/<&'password'&>
+<&'hostname'&>::<&'port'&>(<&'socket name'&>)[<&'option group'&>]/&&&
+ <&'database'&>/<&'user'&>/<&'password'&>
.endd
-Any of the three sub-parts of the first field can be omitted. For normal use on
+Any of the four sub-parts of the first field can be omitted. For normal use on
the local host it can be left blank or set to just &"localhost"&.
No database need be supplied &-- but if it is absent here, it must be given in
different types of pattern for each case are described, but first we cover some
general facilities that apply to all four kinds of list.
+Note that other parts of Exim use a &'string list'& which does not
+support all the complexity available in
+domain, host, address and local part lists.
+
.section "Expansion of lists" "SECID75"
.cindex "&`+ignore_defer`&"
A temporary DNS lookup failure normally causes a defer action (except when
&%dns_again_means_nonexist%& converts it into a permanent error). However,
-host lists can include &`+ignore_defer`& and &`+include_defer`&, analagous to
+host lists can include &`+ignore_defer`& and &`+include_defer`&, analogous to
&`+ignore_unknown`& and &`+include_unknown`&, as described in the previous
section. These options should be used with care, probably only in non-critical
host lists such as whitelists.
.cindex "&%certextract%&" "certificate fields"
.cindex "certificate" "extracting fields"
The <&'certificate'&> must be a variable of type certificate.
-The field name is expanded and used to retrive the relevant field from
+The field name is expanded and used to retrieve the relevant field from
the certificate. Supported fields are:
.display
&`version `&
output a Distinguished Name string which is
not quite
parseable by Exim as a comma-separated tagged list
-(the exceptions being elements containin commas).
+(the exceptions being elements containing commas).
RDN elements of a single type may be selected by
a modifier of the type label; if so the expansion
result is a list (newline-separated by default).
-The separator may be changed by another modifer of
+The separator may be changed by another modifier of
a right angle-bracket followed immediately by the new separator.
Recognised RDN type labels include "CN", "O", "OU" and "DC".
prefix each list element with a type string and an equals sign.
Elements of only one type may be selected by a modifier
which is one of "dns", "uri" or "mail";
-if so the elenment tags are omitted.
+if so the element tags are omitted.
If not otherwise noted field values are presented in human-readable form.
you need to add &%-shared%& to the gcc command. Also, in the Exim build-time
configuration, you must add &%-export-dynamic%& to EXTRALIBS.
+
+.vitem "&*${env{*&<&'key'&>&*}{*&<&'string1'&>&*}{*&<&'string2'&>&*}}*&"
+.cindex "expansion" "extracting value from environment"
+.cindex "environment" "value from"
+The key is first expanded separately, and leading and trailing white space
+removed.
+This is then searched for as a name in the environment.
+If a variable is found then its value is placed in &$value$&
+and <&'string1'&> is expanded, otherwise <&'string2'&> is expanded.
+
+Instead of {<&'string2'&>} the word &"fail"& (not in curly brackets) can
+appear, for example:
+.code
+${env{USER}{$value} fail }
+.endd
+This forces an expansion failure (see section &<<SECTforexpfai>>&);
+{<&'string1'&>} must be present for &"fail"& to be recognized.
+
+If {<&'string2'&>} is omitted an empty string is substituted on
+search failure.
+If {<&'string1'&>} is omitted the search result is substituted on
+search success.
+
+
.vitem "&*${extract{*&<&'key'&>&*}{*&<&'string1'&>&*}{*&<&'string2'&>&*}&&&
{*&<&'string3'&>&*}}*&"
.cindex "expansion" "extracting substrings by key"
Upper case and lower case letters are synonymous in header names. If the
following character is white space, the terminating colon may be omitted, but
this is not recommended, because you may then forget it when it is needed. When
-white space terminates the header name, it is included in the expanded string.
-If the message does not contain the given header, the expansion item is
-replaced by an empty string. (See the &%def%& condition in section
-&<<SECTexpcond>>& for a means of testing for the existence of a header.)
+white space terminates the header name, this white space is included in the
+expanded string. If the message does not contain the given header, the
+expansion item is replaced by an empty string. (See the &%def%& condition in
+section &<<SECTexpcond>>& for a means of testing for the existence of a
+header.)
If there is more than one header with the same name, they are all concatenated
to form the substitution string, up to a maximum length of 64K. Unless
.code
${listextract{-3}{<, x,42,99,& Mailer,,/bin/bash}{result: $value}}
.endd
-yields &"result: 99"&.
+yields &"result: 42"&.
If {<&'string3'&>} is omitted, an empty string is used for string3.
If {<&'string2'&>} is also omitted, the value that was
.vitem &*${sort{*&<&'string'&>&*}{*&<&'comparator'&>&*}{*&<&'extractor'&>&*}}*&
-.cindex sorting a list
+.cindex sorting "a list"
.cindex list sorting
+.cindex expansion "list sorting"
After expansion, <&'string'&> is interpreted as a list, colon-separated by
default, but the separator can be changed in the usual way.
The <&'comparator'&> argument is interpreted as the operator
To clarify "list of addresses in RFC 2822 format" mentioned above, Exim follows
a strict interpretation of header line formatting. Exim parses the bare,
unquoted portion of an email address and if it finds a comma, treats it as an
-email address seperator. For the example header line:
+email address separator. For the example header line:
.code
From: =?iso-8859-2?Q?Last=2C_First?= <user@example.com>
.endd
byte value 127 is converted to &`\x7f`&.
+.new
+.vitem &*${ipv6denorm:*&<&'string'&>&*}*&
+.cindex "&%ipv6denorm%& expansion item"
+.cindex "IP address" normalisation
+This expands an IPv6 address to a full eight-element colon-separated set
+of hex digits including leading zeroes.
+A trailing ipv4-style dotted-decimal set is converted to hex.
+Pure IPv4 addresses are converted to IPv4-mapped IPv6.
+
+.vitem &*${ipv6norm:*&<&'string'&>&*}*&
+.cindex "&%ipv6norm%& expansion item"
+.cindex "IP address" normalisation
+.cindex "IP address" "canonical form"
+This converts an IPv6 address to canonical form.
+Leading zeroes of groups are omitted, and the longest
+set of zero-valued groups is replaced with a double colon.
+A trailing ipv4-style dotted-decimal set is converted to hex.
+Pure IPv4 addresses are converted to IPv4-mapped IPv6.
+.wen
+
+
.vitem &*${lc:*&<&'string'&>&*}*&
.cindex "case forcing in strings"
.cindex "string" "case forcing"
.vitem &*${reverse_ip:*&<&'ipaddr'&>&*}*&
.cindex "expansion" "IP address"
This operator reverses an IP address; for IPv4 addresses, the result is in
-dotted-quad decimal form, while for IPv6 addreses the result is in
+dotted-quad decimal form, while for IPv6 addresses the result is in
dotted-nibble hexadecimal form. In both cases, this is the "natural" form
for DNS. For example,
.code
When a &%match%& expansion condition succeeds, these variables contain the
captured substrings identified by the regular expression during subsequent
processing of the success string of the containing &%if%& expansion item.
-However, they do not retain their values afterwards; in fact, their previous
+In the expansion condition case
+they do not retain their values afterwards; in fact, their previous
values are restored at the end of processing an &%if%& item. The numerical
variables may also be set externally by some other matching process which
precedes the expansion of the string. For example, the commands available in
&$originator_uid$&). If Exim re-execs itself, this variable in the new
incarnation normally contains the Exim uid.
-.vitem &$compile_date$&
-.vindex "&$compile_date$&"
-The date on which the Exim binary was compiled.
+.vitem &$callout_address$&
+.vindex "&$callout_address$&"
+After a callout for verification, spamd or malware daemon service, the
+address that was connected to.
.vitem &$compile_number$&
.vindex "&$compile_number$&"
of times it has been compiled. This serves to distinguish different
compilations of the same version of the program.
-.new
.vitem &$config_dir$&
.vindex "&$config_dir$&"
The directory name of the main configuration file. That is, the content of
.vitem &$config_file$&
.vindex "&$config_file$&"
The name of the main configuration file Exim is using.
-.wen
.vitem &$demime_errorlevel$&
.vindex "&$demime_errorlevel$&"
content-scanning extension and the obsolete &%demime%& condition. For details,
see section &<<SECTdemimecond>>&.
+.vitem &$dkim_cur_signer$& &&&
+ &$dkim_verify_status$& &&&
+ &$dkim_verify_reason$& &&&
+ &$dkim_domain$& &&&
+ &$dkim_identity$& &&&
+ &$dkim_selector$& &&&
+ &$dkim_algo$& &&&
+ &$dkim_canon_body$& &&&
+ &$dkim_canon_headers$& &&&
+ &$dkim_copiedheaders$& &&&
+ &$dkim_bodylength$& &&&
+ &$dkim_created$& &&&
+ &$dkim_expires$& &&&
+ &$dkim_headernames$& &&&
+ &$dkim_key_testing$& &&&
+ &$dkim_key_nosubdomains$& &&&
+ &$dkim_key_srvtype$& &&&
+ &$dkim_key_granularity$& &&&
+ &$dkim_key_notes$&
+These variables are only available within the DKIM ACL.
+For details see chapter &<<CHAPdkim>>&.
+
+.vitem &$dkim_signers$&
+.vindex &$dkim_signers$&
+When a message has been received this variable contains
+a colon-separated list of signer domains and identities for the message.
+For details see chapter &<<CHAPdkim>>&.
+
.vitem &$dnslist_domain$& &&&
&$dnslist_matched$& &&&
&$dnslist_text$& &&&
.vindex "&$exim_uid$&"
This variable contains the numerical value of the Exim user id.
-.new
.vitem &$exim_version$&
-.vindex "&$exim_uid$&"
+.vindex "&$exim_version$&"
This variable contains the version string of the Exim build.
The first character is a major version number, currently 4.
Then after a dot, the next group of digits is a minor version number.
There may be other characters following the minor version.
-.wen
.vitem &$found_extension$&
.vindex "&$found_extension$&"
.vindex "&$lookup_dnssec_authenticated$&"
This variable is set after a DNS lookup done by
a dnsdb lookup expansion, dnslookup router or smtp transport.
+.cindex "DNS" "DNSSEC"
It will be empty if &(DNSSEC)& was not requested,
&"no"& if the result was not labelled as authenticated data
and &"yes"& if it was.
+Results that are labelled as authoritative answer that match
+the &%dns_trust_aa%& configuration variable count also
+as authenticated data.
.vitem &$mailstore_basename$&
.vindex "&$mailstore_basename$&"
qualified host name. See also &$smtp_active_hostname$&.
+.new
+.vitem &$prdr_requested$&
+.cindex "PRDR" "variable for"
+This variable is set to &"yes"& if PRDR was requested by the client for the
+current message, otherwise &"no"&.
+.wen
+
.vitem &$prvscheck_address$&
This variable is used in conjunction with the &%prvscheck%& expansion item,
which is described in sections &<<SECTexpansionitems>>& and
This variable is set to contain the matching regular expression after a
&%regex%& ACL condition has matched (see section &<<SECTscanregex>>&).
+.vitem "&$regex1$&, &$regex2$&, etc"
+.cindex "regex submatch variables (&$1regex$& &$2regex$& etc)"
+When a &%regex%& or &%mime_regex%& ACL condition succeeds,
+these variables contain the
+captured substrings identified by the regular expression.
+
.vitem &$reply_address$&
.vindex "&$reply_address$&"
the argument of a HELO or EHLO command. This is omitted if it is identical to
the verified host name or to the host's IP address in square brackets.
+.vitem &$sender_helo_dnssec$&
+.vindex "&$sender_helo_dnssec$&"
+This boolean variable is true if a successful HELO verification was
+.cindex "DNS" "DNSSEC"
+done using DNS information the resolver library stated was authenticated data.
+
.vitem &$sender_helo_name$&
.vindex "&$sender_helo_name$&"
When a message is received from a remote host that has issued a HELO or EHLO
If an attempt to populate &$sender_host_name$& has been made
(by reference, &%hosts_lookup%& or
otherwise) then this boolean will have been set true if, and only if, the
-resolver library states that the reverse DNS was authenticated data. At all
+resolver library states that both
+the reverse and forward DNS were authenticated data. At all
other times, this variable is false.
+.cindex "DNS" "DNSSEC"
It is likely that you will need to coerce DNSSEC support on in the resolver
library, by setting:
.code
.endd
Exim does not perform DNSSEC validation itself, instead leaving that to a
-validating resolver (eg, unbound, or bind with suitable configuration).
-
-Exim does not (currently) check to see if the forward DNS was also secured
-with DNSSEC, only the reverse DNS.
+validating resolver (e.g. unbound, or bind with suitable configuration).
If you have changed &%host_lookup_order%& so that &`bydns`& is not the first
mechanism in the list, then this variable will be false.
This variable is set to &"1"& if a TLS certificate was verified when the
message was received, and &"0"& otherwise.
-The deprecated &$tls_certificate_verfied$& variable refers to the inbound side
+The deprecated &$tls_certificate_verified$& variable refers to the inbound side
except when used in the context of an outbound SMTP delivery, when it refers to
the outbound.
.row &%message_logs%& "create per-message logs"
.row &%preserve_message_logs%& "after message completion"
.row &%process_log_path%& "for SIGUSR1 and &'exiwhat'&"
+.row &%slow_lookup_log%& "control logging of slow DNS lookups"
.row &%syslog_duplication%& "controls duplicate log lines on syslog"
.row &%syslog_facility%& "set syslog &""facility""& field"
.row &%syslog_processname%& "set syslog &""ident""& field"
.row &%tls_crl%& "certificate revocation list"
.row &%tls_dh_max_bits%& "clamp D-H bit count suggestion"
.row &%tls_dhparam%& "DH parameters for server"
+.row &%tls_eccurve%& "EC curve selection for server"
.row &%tls_ocsp_file%& "location of server certificate status proof"
.row &%tls_on_connect_ports%& "specify SSMTP (SMTPS) ports"
.row &%tls_privatekey%& "location of server private key"
See also the &'Policy controls'& section above.
.table2
+.row &%dkim_verify_signers%& "DKIM domain for which DKIM ACL is run"
.row &%host_lookup%& "host name looked up for these hosts"
.row &%host_lookup_order%& "order of DNS and local name lookups"
.row &%recipient_unqualified_hosts%& "may send unqualified recipients"
.row &%dns_ipv4_lookup%& "only v4 lookup for these domains"
.row &%dns_retrans%& "parameter for resolver"
.row &%dns_retry%& "parameter for resolver"
+.row &%dns_trust_aa%& "DNS zones trusted as authentic"
.row &%dns_use_edns0%& "parameter for resolver"
.row &%hold_domains%& "hold delivery for these domains"
.row &%local_interfaces%& "for routing checks"
processed and the message itself has been received, but before the final
acknowledgment is sent. See chapter &<<CHAPACL>>& for further details.
-.new
.option acl_smtp_data_prdr main string&!! accept
.cindex "PRDR" "ACL for"
.cindex "DATA" "PRDR ACL for"
.cindex "&ACL;" "PRDR-related"
.cindex "&ACL;" "per-user data processing"
-.wen
This option defines the ACL that,
if the PRDR feature has been negotiated,
is run for each recipient after an SMTP DATA command has been
processed and the message itself has been received, but before the
acknowledgment is sent. See chapter &<<CHAPACL>>& for further details.
+.option acl_smtp_dkim main string&!! unset
+.cindex DKIM "ACL for"
+This option defines the ACL that is run for each DKIM signature
+of a received message.
+See chapter &<<CHAPdkim>>& for further details.
+
.option acl_smtp_etrn main string&!! unset
.cindex "ETRN" "ACL for"
This option defines the ACL that is run when an SMTP ETRN command is
It appears that more and more DNS zone administrators are breaking the rules
and putting domain names that look like IP addresses on the right hand side of
MX records. Exim follows the rules and rejects this, giving an error message
-that explains the mis-configuration. However, some other MTAs support this
+that explains the misconfiguration. However, some other MTAs support this
practice, so to avoid &"Why can't Exim do this?"& complaints,
&%allow_mx_to_ip%& exists, in order to enable this heinous activity. It is not
recommended, except when you have no other choice.
to handle IPv6 literal addresses.
+.option dkim_verify_signers main "domain list&!!" $dkim_signers
+.cindex DKIM "controlling calls to the ACL"
+This option gives a list of DKIM domains for which the DKIM ACL is run.
+It is expanded after the message is received; by default it runs
+the ACL once for each signature in the message.
+See chapter &<<CHAPdkim>>&.
+
+
.option dns_again_means_nonexist main "domain list&!!" unset
.cindex "DNS" "&""try again""& response; overriding"
DNS lookups give a &"try again"& response for the DNS errors
.option dns_retrans main time 0s
.cindex "DNS" "resolver options"
+.cindex timeout "dns lookup"
+.cindex "DNS" timeout
The options &%dns_retrans%& and &%dns_retry%& can be used to set the
retransmission and retry parameters for DNS lookups. Values of zero (the
defaults) leave the system default settings unchanged. The first value is the
parameter values are available in the external resolver interface structure,
but nowhere does it seem to describe how they are used or what you might want
to set in them.
+See also the &%slow_lookup_log%& option.
.option dns_retry main integer 0
See &%dns_retrans%& above.
+.option dns_trust_aa main "domain list&!!" unset
+.cindex "DNS" "resolver options"
+.cindex "DNS" "DNSSEC"
+If this option is set then lookup results marked with the AA bit
+(Authoritative Answer) are trusted the same way as if they were
+DNSSEC-verified. The authority section's name of the answer must
+match with this expanded domain list.
+
+Use this option only if you talk directly to a resolver that is
+authoritative for some zones and does not set the AD (Authentic Data)
+bit in the answer. Some DNS servers may have an configuration option to
+mark the answers from their own zones as verified (they set the AD bit).
+Others do not have this option. It is considered as poor practice using
+a resolver that is an authoritative server for some zones.
+
+Use this option only if you really have to (e.g. if you want
+to use DANE for remote delivery to a server that is listed in the DNS
+zones that your resolver is authoritative for).
+
+If the DNS answer packet has the AA bit set and contains resource record
+in the answer section, the name of the first NS record appearing in the
+authority section is compared against the list. If the answer packet is
+authoritative but the answer section is empty, the name of the first SOA
+record in the authoritative section is used instead.
+
+.cindex "DNS" "resolver options"
.option dns_use_edns0 main integer -1
.cindex "DNS" "resolver options"
.cindex "DNS" "EDNS0"
handled CR and LF characters in incoming messages. What happens now is
described in section &<<SECTlineendings>>&.
-.new
.option dsn_advertise_hosts main "host list&!!" unset
.cindex "bounce messages" "success"
.cindex "DSN" "success"
A NOTIFY=SUCCESS option requests success-DSN messages.
A NOTIFY= option with no argument requests that no delay or failure DSNs
are sent.
-.wen
.option dsn_from main "string&!!" "see below"
.cindex "&'From:'& header line" "in bounces"
Exim's transports have an option for adding an &'Envelope-to:'& header to a
message when it is delivered, in exactly the same way as &'Return-path:'& is
handled. &'Envelope-to:'& records the original recipient address from the
-messages's envelope that caused the delivery to happen. Such headers should not
+message's envelope that caused the delivery to happen. Such headers should not
be present in incoming messages, and this option causes them to be removed at
the time the message is received, to avoid any problems that might occur when a
delivered message is subsequently sent on to some other recipient.
. Allow this long option name to split; give it unsplit as a fifth argument
. for the automatic .oindex that is generated by .option.
-.option "extract_addresses_remove_ &~&~arguments" main boolean true &&&
+.option "extract_addresses_remove_arguments" main boolean true &&&
extract_addresses_remove_arguments
.oindex "&%-t%&"
.cindex "command line" "addresses with &%-t%&"
matches the host name that Exim obtains by doing a reverse lookup of the
calling host address, or
.next
-when looked up using &[gethostbyname()]& (or &[getipnodebyname()]& when
-available) yields the calling host address.
+when looked up in DNS yields the calling host address.
.endlist
However, the EHLO or HELO command is not rejected if any of the checks
fail. Processing continues, but the result of the check is remembered, and can
be detected later in an ACL by the &`verify = helo`& condition.
+If DNS was used for successful verification, the variable
+.cindex "DNS" "DNSSEC"
+&$helo_verify_dnssec$& records the DNSSEC status of the lookups.
+
.option helo_verify_hosts main "host list&!!" unset
.cindex "HELO verifying" "mandatory"
.cindex "EHLO" "verifying, mandatory"
This option sets the path which is used to determine the names of Exim's log
files, or indicates that logging is to be to syslog, or both. It is expanded
when Exim is entered, so it can, for example, contain a reference to the host
-name. If no specific path is set for the log files at compile or run time, they
-are written in a sub-directory called &_log_& in Exim's spool directory.
+name. If no specific path is set for the log files at compile or run time,
+or if the option is unset at run time (i.e. &`log_file_path = `&)
+they are written in a sub-directory called &_log_& in Exim's spool directory.
Chapter &<<CHAPlog>>& contains further details about Exim's logging, and
section &<<SECTwhelogwri>>& describes how the contents of &%log_file_path%& are
used. If this string is fixed at your installation (contains no expansion
maximum size that your virus-scanner is configured to support, you may get
failures triggered by large mails. The right size to configure for the
virus-scanner depends upon what data is passed and the options in use but it's
-probably safest to just set it to a little larger than this value. Eg, with a
+probably safest to just set it to a little larger than this value. E.g., with a
default Exim message size of 50M and a default ClamAV StreamMaxLength of 10M,
some problems may result.
This option can be used to enable the Per-Recipient Data Response extension
to SMTP, defined by Eric Hall.
If the option is set, PRDR is advertised by Exim when operating as a server.
-If the client requests PRDR, and more than one recipient, for a message
+If the client requests PRDR, and more than one recipient, for a message
an additional ACL is called for each recipient after the message content
-is recieved. See section &<<SECTPRDRACL>>&.
+is received. See section &<<SECTPRDRACL>>&.
.option preserve_message_logs main boolean false
.cindex "message logs" "preserving"
This option is an obsolete synonym for &%bounce_return_size_limit%&.
-.new
.option rfc1413_hosts main "host list&!!" @[]
.cindex "RFC 1413"
.cindex "host" "for RFC 1413 calls"
an item in the list.
The default value specifies just this host, being any local interface
for the system.
-.wen
-.new
.option rfc1413_query_timeout main time 0s
-.wen
.cindex "RFC 1413" "query timeout"
.cindex "timeout" "for RFC 1413 call"
This sets the timeout on RFC 1413 identification calls. If it is set to zero,
using TCP/IP), and the &%-bnq%& option was not set.
+.option slow_lookup_log main integer 0
+.cindex "logging" "slow lookups"
+.cindex "dns" "logging slow lookups"
+This option controls logging of slow lookups.
+If the value is nonzero it is taken as a number of milliseconds
+and lookups taking longer than this are logged.
+Currently this applies only to DNS lookups.
+
+
+
.option smtp_accept_keepalive main boolean true
.cindex "keepalive" "on incoming connection"
This option controls the setting of the SO_KEEPALIVE option on incoming
unfortunately not all, operating systems.
-.option tls_advertise_hosts main "host list&!!" unset
+.new
+.option tls_advertise_hosts main "host list&!!" *
+.wen
.cindex "TLS" "advertising"
.cindex "encryption" "on SMTP connection"
.cindex "SMTP" "encrypted connection"
of the STARTTLS command to set up an encrypted session is advertised in
response to EHLO only to those client hosts that match this option. See
chapter &<<CHAPTLS>>& for details of Exim's support for TLS.
+.new
+Note that the default value requires that a certificate be supplied
+using the &%tls_certificate%& option. If no certificate is available then
+the &%tls_advertise_hosts%& option should be set empty.
+.wen
.option tls_certificate main string&!! unset
acceptable bound from 1024 to 2048.
+.option tls_eccurve main string&!! prime256v1
+.cindex TLS "EC cryptography"
+If built with a recent-enough version of OpenSSL,
+this option selects a EC curve for use by Exim.
+
+Curve names of the form &'prime256v1'& are accepted.
+For even more-recent library versions, names of the form &'P-512'&
+are also accepted, plus the special value &'auto'&
+which tell the library to choose.
+
+If the option is set to an empty string, no EC curves will be enabled.
+
+
.option tls_ocsp_file main string&!! unset
+.cindex TLS "certificate status"
+.cindex TLS "OCSP proof file"
This option
must if set expand to the absolute path to a file which contains a current
status proof for the server's certificate, as obtained from the
Certificate Authority.
+.new
+Usable for GnuTLS 3.4.4 or 3.3.17 or OpenSSL 1.1.0 (or later).
+.wen
+
.option tls_on_connect_ports main "string list" unset
+.cindex SSMTP
+.cindex SMTPS
This option specifies a list of incoming SSMTP (aka SMTPS) ports that should
operate the obsolete SSMTP (SMTPS) protocol, where a TLS session is immediately
set up without waiting for the client to issue a STARTTLS command. For
See &%tls_verify_hosts%& below.
-.new
.option tls_verify_certificates main string&!! system
.cindex "TLS" "client certificate verification"
.cindex "certificate" "verification of client"
and will be taken as empty; an explicit location
must be specified.
-The use of a directory for the option value is not avilable for GnuTLS versions
+The use of a directory for the option value is not available for GnuTLS versions
preceding 3.3.6 and a single file must be used.
With OpenSSL the certificates specified
explicitly
either by file or directory
are added to those given by the system default location.
-.wen
These certificates should be for the certificate authorities trusted, rather
than the public cert of individual clients. With both OpenSSL and GnuTLS, if
unless you really, really know what you are doing. See also the generic
transport option of the same name.
+.option dnssec_request_domains routers "domain list&!!" unset
+.cindex "MX record" "security"
+.cindex "DNSSEC" "MX lookup"
+.cindex "security" "MX lookup"
+.cindex "DNS" "DNSSEC"
+DNS lookups for domains matching &%dnssec_request_domains%& will be done with
+the dnssec request bit set.
+This applies to all of the SRV, MX, AAAA, A lookup sequence.
+
+.option dnssec_require_domains routers "domain list&!!" unset
+.cindex "MX record" "security"
+.cindex "DNSSEC" "MX lookup"
+.cindex "security" "MX lookup"
+.cindex "DNS" "DNSSEC"
+DNS lookups for domains matching &%dnssec_request_domains%& will be done with
+the dnssec request bit set. Any returns not having the Authenticated Data bit
+(AD bit) set will be ignored and logged as a host-lookup failure.
+This applies to all of the SRV, MX, AAAA, A lookup sequence.
+
.option domains routers&!? "domain list&!!" unset
.cindex "router" "restricting to specific domains"
to be used.
-.new
.option dsn_lasthop routers boolean false
.cindex "DSN" "success"
.cindex "Delivery Status Notification" "success"
Exim will not pass on DSN requests to downstream DSN-aware hosts but will
instead send a success DSN as if the next hop does not support DSN.
Not effective on redirect routers.
-.wen
.cindex "header lines" "adding"
.cindex "router" "adding header lines"
This option specifies a list of text headers,
-.new
newline-separated (by default, changeable in the usual way),
-.wen
that is associated with any addresses that are accepted by the router.
Each item is separately expanded, at routing time. However, this
option has no effect when an address is just being verified. The way in which
.cindex "header lines" "removing"
.cindex "router" "removing header lines"
This option specifies a list of text headers,
-.new
colon-separated (by default, changeable in the usual way),
-.wen
that is associated with any addresses that are accepted by the router.
Each item is separately expanded, at routing time. However, this
option has no effect when an address is just being verified. The way in which
routers, and this can lead to problems with duplicates -- see the similar
warning for &%headers_add%& above.
+&*Warning 3*&: Because of the separate expansion of the list items,
+items that contain a list separator must have it doubled.
+To avoid this, change the list separator (&<<SECTlistsepchange>>&).
+
+
.option ignore_target_hosts routers "host list&!!" unset
.cindex "IP address" "discarding"
.section "Problems with DNS lookups" "SECTprowitdnsloo"
There have been problems with DNS servers when SRV records are looked up.
-Some mis-behaving servers return a DNS error or timeout when a non-existent
+Some misbehaving servers return a DNS error or timeout when a non-existent
SRV record is sought. Similar problems have in the past been reported for
MX records. The global &%dns_again_means_nonexist%& option can help with this
problem, but it is heavy-handed because it is a global option.
-.option dnssec_request_domains dnslookup "domain list&!!" unset
-.cindex "MX record" "security"
-.cindex "DNSSEC" "MX lookup"
-.cindex "security" "MX lookup"
-.cindex "DNS" "DNSSEC"
-DNS lookups for domains matching &%dnssec_request_domains%& will be done with
-the dnssec request bit set.
-This applies to all of the SRV, MX, AAAA, A lookup sequence.
-
-
-
-.option dnssec_require_domains dnslookup "domain list&!!" unset
-.cindex "MX record" "security"
-.cindex "DNSSEC" "MX lookup"
-.cindex "security" "MX lookup"
-.cindex "DNS" "DNSSEC"
-DNS lookups for domains matching &%dnssec_request_domains%& will be done with
-the dnssec request bit set. Any returns not having the Authenticated Data bit
-(AD bit) set wil be ignored and logged as a host-lookup failure.
-This applies to all of the SRV, MX, AAAA, A lookup sequence.
-
-
.option fail_defer_domains dnslookup "domain list&!!" unset
.cindex "MX record" "not found"
files and pipes, and for generating autoreplies. See the &%file_transport%&,
&%pipe_transport%& and &%reply_transport%& descriptions below.
-.new
If success DSNs have been requested
.cindex "DSN" "success"
.cindex "Delivery Status Notification" "success"
redirection triggers one and the DSN options are not passed any further.
-.wen
.cindex "black hole"
.cindex "abandoning mail"
&':blackhole:'& can be used. It does what its name implies. No delivery is
-done, and no error message is generated. This has the same effect as specifing
+done, and no error message is generated. This has the same effect as specifying
&_/dev/null_& as a destination, but it can be independently disabled.
&*Warning*&: If &':blackhole:'& appears anywhere in a redirection list, no
.cindex "header lines" "adding in transport"
.cindex "transport" "header lines; adding"
This option specifies a list of text headers,
-.new
newline-separated (by default, changeable in the usual way),
-.wen
which are (separately) expanded and added to the header
portion of a message as it is transported, as described in section
&<<SECTheadersaddrem>>&. Additional header lines can also be specified by
.cindex "header lines" "removing"
.cindex "transport" "header lines; removing"
This option specifies a list of header names,
-.new
colon-separated (by default, changeable in the usual way);
-.wen
these headers are omitted from the message as it is transported, as described
in section &<<SECTheadersaddrem>>&. Header removal can also be specified by
routers.
Unlike most options, &%headers_remove%& can be specified multiple times
for a router; all listed headers are removed.
+&*Warning*&: Because of the separate expansion of the list items,
+items that contain a list separator must have it doubled.
+To avoid this, change the list separator (&<<SECTlistsepchange>>&).
+
.option headers_rewrite transports string unset
to ensure that any additional groups associated with the uid are set up.
+.new
+.option max_parallel transports integer&!! unset
+.cindex limit "transport parallelism"
+.cindex transport "parallel processes"
+.cindex transport "concurrency limit"
+.cindex "delivery" "parallelism for transport"
+If this option is set and expands to an integer greater than zero
+it limits the number of concurrent runs of the transport.
+The control does not apply to shadow transports.
+
+.cindex "hints database" "transport concurrency control"
+Exim implements this control by means of a hints database in which a record is
+incremented whenever a transport process is beaing created. The record
+is decremented and possibly removed when the process terminates.
+Obviously there is scope for
+records to get left lying around if there is a system or program crash. To
+guard against this, Exim ignores any records that are more than six hours old.
+
+If you use this option, you should also arrange to delete the
+relevant hints database whenever your system reboots. The names of the files
+start with &_misc_& and they are kept in the &_spool/db_& directory. There
+may be one or two files, depending on the type of DBM in use. The same files
+are used for ETRN and smtp transport serialization.
+.wen
+
+
.option message_size_limit transports string&!! 0
.cindex "limit" "message size per transport"
.cindex "size" "of message, limit"
This option sets up a filtering (in the Unix shell sense) process for messages
at transport time. It should not be confused with mail filtering as set up by
individual users or via a system filter.
+.new
+If unset, or expanding to an empty string, no filtering is done.
+.wen
When the message is about to be written out, the command specified by
&%transport_filter%& is started up in a separate, parallel process, and
delivery, the two pipe transports may be run concurrently. You must ensure that
any pipe commands you set up are robust against this happening. If the commands
write to a file, the &%exim_lock%& utility might be of use.
+.new
+Alternatively the &%max_parallel%& option could be used with a value
+of "1" to enforce serialization.
+.wen
&%force_command%& is set, expanding out to the original argument vector as
separate items, similarly to a Unix shell &`"$@"`& construct.
+
.option ignore_status pipe boolean false
If this option is true, the status returned by the subprocess that is set up to
run the command is ignored, and Exim behaves as if zero had been returned.
&*Note*&: This option does not apply to timeouts, which do not return a status.
See the &%timeout_defer%& option for how timeouts are handled.
+
.option log_defer_output pipe boolean false
.cindex "&(pipe)& transport" "logging output"
If this option is set, and the status returned by the command is
one of the codes listed in &%temp_errors%& (that is, delivery was deferred),
-and any output was produced, the first line of it is written to the main log.
+and any output was produced on stdout or stderr, the first line of it is
+written to the main log.
.option log_fail_output pipe boolean false
-If this option is set, and the command returns any output, and also ends with a
-return code that is neither zero nor one of the return codes listed in
-&%temp_errors%& (that is, the delivery failed), the first line of output is
-written to the main log. This option and &%log_output%& are mutually exclusive.
-Only one of them may be set.
-
+If this option is set, and the command returns any output on stdout or
+stderr, and also ends with a return code that is neither zero nor one of
+the return codes listed in &%temp_errors%& (that is, the delivery
+failed), the first line of output is written to the main log. This
+option and &%log_output%& are mutually exclusive. Only one of them may
+be set.
.option log_output pipe boolean false
-If this option is set and the command returns any output, the first line of
-output is written to the main log, whatever the return code. This option and
-&%log_fail_output%& are mutually exclusive. Only one of them may be set.
-
+If this option is set and the command returns any output on stdout or
+stderr, the first line of output is written to the main log, whatever
+the return code. This option and &%log_fail_output%& are mutually
+exclusive. Only one of them may be set.
.option max_output pipe integer 20K
.cindex "DNS" "DNSSEC"
DNS lookups for domains matching &%dnssec_request_domains%& will be done with
the dnssec request bit set. Any returns not having the Authenticated Data bit
-(AD bit) set wil be ignored and logged as a host-lookup failure.
+(AD bit) set will be ignored and logged as a host-lookup failure.
This applies to all of the SRV, MX, AAAA, A lookup sequence.
Exim will not try to start a TLS session when delivering to any host that
matches this list. See chapter &<<CHAPTLS>>& for details of TLS.
-.option hosts_verify_avoid_tls smtp "host list&!!" *
+.option hosts_verify_avoid_tls smtp "host list&!!" unset
.cindex "TLS" "avoiding for certain hosts"
Exim will not try to start a TLS session for a verify callout,
or when delivering in cutthrough mode,
to any host that matches this list.
-Note that the default is to not use TLS.
.option hosts_max_try smtp integer 5
unauthenticated. See also &%hosts_require_auth%&, and chapter
&<<CHAPSMTPAUTH>>& for details of authentication.
-.new
.option hosts_try_prdr smtp "host list&!!" *
.cindex "PRDR" "enabling, optional in client"
This option provides a list of servers to which, provided they announce
PRDR support, Exim will attempt to negotiate PRDR
for multi-recipient messages.
The option can usually be left as default.
-.wen
.option interface smtp "string list&!!" unset
.cindex "bind IP address"
&$domain$& in an expansion for the transport, because it is set only when there
is a single domain involved in a remote delivery.
-.new
It is expanded per-address and can depend on any of
&$address_data$&, &$domain_data$&, &$local_part_data$&,
&$host$&, &$host_address$& and &$host_port$&.
-.wen
.option port smtp string&!! "see below"
.cindex "port" "sending TCP/IP"
deliveries into closed message stores. Exim also has support for running LMTP
over a pipe to a local process &-- see chapter &<<CHAPLMTP>>&.
-If this option is set to &"smtps"&, the default vaule for the &%port%& option
+If this option is set to &"smtps"&, the default value for the &%port%& option
changes to &"smtps"&, and the transport initiates TLS immediately after
connecting, as an outbound SSL-on-connect, instead of using STARTTLS to upgrade.
The Internet standards bodies strongly discourage use of this mode.
each time they connect. In this situation the use of the IP address as part of
the retry key leads to undesirable behaviour. Setting this option false causes
Exim to use only the host name.
-.new
Since it is expanded it can be made to depend on the host or domain.
-.wen
.option serialize_hosts smtp "host list&!!" unset
may be one or two files, depending on the type of DBM in use. The same files
are used for ETRN serialization.
+.new
+See also the &%max_parallel%& generic transport option.
+.wen
+
.option size_addition smtp integer 1024
.cindex "SMTP" "SIZE"
in clear.
-.new
.option tls_try_verify_hosts smtp "host list&!!" *
-.wen
.cindex "TLS" "server certificate verification"
.cindex "certificate" "verification of server"
This option gives a list of hosts for which, on encrypted connections,
certificate verification succeeds.
-.new
.option tls_verify_cert_hostnames smtp "host list&!!" *
.cindex "TLS" "server certificate hostname verification"
.cindex "certificate" "verification of server"
limited to being the initial component of a 3-or-more component FQDN.
There is no equivalent checking on client certificates.
-.wen
-.new
.option tls_verify_certificates smtp string&!! system
.cindex "TLS" "server certificate verification"
.cindex "certificate" "verification of server"
is taken as empty and an explicit location
must be specified.
-The use of a directory for the option value is not avilable for GnuTLS versions
+The use of a directory for the option value is not available for GnuTLS versions
preceding 3.3.6 and a single file must be used.
-.wen
With OpenSSL the certificates specified
explicitly
&$host_address$& are set to the name and address of the server during the
expansion of this option. See chapter &<<CHAPTLS>>& for details of TLS.
-For back-compatability,
+For back-compatibility,
if neither tls_verify_hosts nor tls_try_verify_hosts are set
(a single-colon empty list counts as being set)
and certificate verification fails the TLS connection is closed.
AUTH_HEIMDAL_GSSAPI=yes
AUTH_PLAINTEXT=yes
AUTH_SPA=yes
+AUTH_TLS=yes
.endd
in &_Local/Makefile_&, respectively. The first of these supports the CRAM-MD5
authentication mechanism (RFC 2195), and the second provides an interface to
the PLAIN authentication mechanism (RFC 2595) or the LOGIN mechanism, which is
not formally documented, but used by several MUAs. The seventh authenticator
supports Microsoft's &'Secure Password Authentication'& mechanism.
+The eighth is an Exim authenticator but not an SMTP one;
+instead it can use information from a TLS negotiation.
The authenticators are configured using the same syntax as other drivers (see
section &<<SECTfordricon>>&). If no authenticators are required, no
.option client_set_id authenticators string&!! unset
When client authentication succeeds, this condition is expanded; the
-result is used in the log lines for outbound messasges.
+result is used in the log lines for outbound messages.
Typically it will be the user name used for authentication.
driver = cram_md5
public_name = CRAM-MD5
server_secret = ${lookup{$auth1:mail.example.org:userPassword}\
- dbmjz{/etc/sasldb2}}
+ dbmjz{/etc/sasldb2}{$value}fail}
server_set_id = $auth1
.endd
.option server_service heimdal_gssapi string&!! "smtp"
This option specifies the service identifier used, in conjunction with
-&%server_hostname%&, for building the identifer for finding credentials
+&%server_hostname%&, for building the identifier for finding credentials
from the keytab.
+. ////////////////////////////////////////////////////////////////////////////
+. ////////////////////////////////////////////////////////////////////////////
+
+.chapter "The tls authenticator" "CHAPtlsauth"
+.scindex IIDtlsauth1 "&(tls)& authenticator"
+.scindex IIDtlsauth2 "authenticators" "&(tls)&"
+.cindex "authentication" "Client Certificate"
+.cindex "authentication" "X509"
+.cindex "Certificate-based authentication"
+The &(tls)& authenticator provides server support for
+authentication based on client certificates.
+
+It is not an SMTP authentication mechanism and is not
+advertised by the server as part of the SMTP EHLO response.
+It is an Exim authenticator in the sense that it affects
+the protocol element of the log line, can be tested for
+by the &%authenticated%& ACL condition, and can set
+the &$authenticated_id$& variable.
+
+The client must present a verifiable certificate,
+for which it must have been requested via the
+&%tls_verify_hosts%& or &%tls_try_verify_hosts%& main options
+(see &<<CHAPTLS>>&).
+
+If an authenticator of this type is configured it is
+run before any SMTP-level communication is done,
+and can authenticate the connection.
+If it does, SMTP authentication is not offered.
+
+A maximum of one authenticator of this type may be present.
+
+
+.cindex "options" "&(tls)& authenticator (server)"
+The &(tls)& authenticator has three server options:
+
+.option server_param1 tls string&!! unset
+.cindex "variables (&$auth1$& &$auth2$& etc)" "in &(tls)& authenticator"
+This option is expanded after the TLS negotiation and
+the result is placed in &$auth1$&.
+If the expansion is forced to fail, authentication fails. Any other expansion
+failure causes a temporary error code to be returned.
+
+.option server_param2 tls string&!! unset
+.option server_param3 tls string&!! unset
+As above, for &$auth2$& and &$auth3$&.
+
+&%server_param1%& may also be spelled &%server_param%&.
+
+
+Example:
+.code
+tls:
+ driver = tls
+ server_param1 = ${certextract {subj_altname,mail,>:} \
+ {$tls_in_peercert}}
+ server_condition = ${if forany {$auth1} \
+ {!= {0} \
+ {${lookup ldap{ldap:///\
+ mailname=${quote_ldap_dn:${lc:$item}},\
+ ou=users,LDAP_DC?mailid} {$value}{0} \
+ } } } }
+ server_set_id = ${if = {1}{${listcount:$auth1}} {$auth1}{}}
+.endd
+.ecindex IIDtlsauth1
+.ecindex IIDtlsauth2
+
+
+Note that because authentication is traditionally an SMTP operation,
+the &%authenticated%& ACL condition cannot be used in
+a connect- or helo-ACL.
+
+
+
. ////////////////////////////////////////////////////////////////////////////
. ////////////////////////////////////////////////////////////////////////////
Exim requests a certificate as part of the setup of the TLS session. The
contents of the certificate are verified by comparing it with a list of
expected certificates.
-.new
These may be the system default set (depending on library version),
-.wen
an explicit file or,
depending on library version, a directory, identified by
&%tls_verify_certificates%&.
proof expires. The downside is that it requires server support.
Unless Exim is built with the support disabled,
-or with GnuTLS earlier than version 3.1.3,
+.new
+or with GnuTLS earlier than version 3.3.16 / 3.4.8
+.wen
support for OCSP stapling is included.
There is a global option called &%tls_ocsp_file%&.
If the &%tls_verify_certificates%& option is set on the &(smtp)& transport, it
specifies a collection of expected server certificates.
-.new
These may be the system default set (depending on library version),
-.wen
a file or,
-depnding on liibrary version, a directory,
+depending on library version, a directory,
must name a file or,
for OpenSSL only (not GnuTLS), a directory.
The client verifies the server's certificate
within and possibly choose to use different certificates and keys (and more)
for this session.
-This is analagous to HTTP's &"Host:"& header, and is the main mechanism by
+This is analogous to HTTP's &"Host:"& header, and is the main mechanism by
which HTTPS-enabled web-sites can be virtual-hosted, many sites to one IP
address.
The Exim developers are proceeding cautiously and so far no other TLS options
are re-expanded.
-When Exim is built againt OpenSSL, OpenSSL must have been built with support
+When Exim is built against OpenSSL, OpenSSL must have been built with support
for TLS Extensions. This holds true for OpenSSL 1.0.0+ and 0.9.8+ with
enable-tlsext in EXTRACONFIGURE. If you invoke &(openssl s_client -h)& and
see &`-servername`& in the output, then OpenSSL has support.
.cindex "EXPN" "ACL for"
.cindex "HELO" "ACL for"
.cindex "EHLO" "ACL for"
+.cindex "DKIM" "ACL for"
.cindex "MAIL" "ACL for"
.cindex "QUIT, ACL for"
.cindex "RCPT" "ACL for"
.irow &%acl_smtp_connect%& "ACL for start of SMTP connection"
.irow &%acl_smtp_data%& "ACL after DATA is complete"
.irow &%acl_smtp_data_prdr%& "ACL for each recipient, after DATA is complete"
+.irow &%acl_smtp_dkim%& "ACL for each DKIM signer"
.irow &%acl_smtp_etrn%& "ACL for ETRN"
.irow &%acl_smtp_expn%& "ACL for EXPN"
.irow &%acl_smtp_helo%& "ACL for HELO or EHLO"
client and server for a message, and more than one recipient
has been accepted.
-The ACL test specfied by &%acl_smtp_data_prdr%& happens after a message
-has been recieved, and is executed once for each recipient of the message
+The ACL test specified by &%acl_smtp_data_prdr%& happens after a message
+has been received, and is executed once for each recipient of the message
with &$local_part$& and &$domain$& valid.
-The test may accept, defer or deny for inividual recipients.
+The test may accept, defer or deny for individual recipients.
The &%acl_smtp_data%& will still be called after this ACL and
can reject the message overall, even if this ACL has accepted it
for some or all recipients.
PRDR may be used to support per-user content filtering. Without it
one must defer any recipient after the first that has a different
content-filter configuration. With PRDR, the RCPT-time check
-for this can be disabled when the MAIL-time $smtp_command included
-"PRDR". Any required difference in behaviour of the main DATA-time
+.new
+.cindex "PRDR" "variable for"
+for this can be disabled when the variable &$prdr_requested$&
+is &"yes"&.
+.wen
+Any required difference in behaviour of the main DATA-time
ACL should however depend on the PRDR-time ACL having run, as Exim
-will avoid doing so in some situations (eg. single-recipient mails).
+will avoid doing so in some situations (e.g. single-recipient mails).
See also the &%prdr_enable%& global option
and the &%hosts_try_prdr%& smtp transport option.
.cindex "QUIT, ACL for"
The ACL for the SMTP QUIT command is anomalous, in that the outcome of the ACL
does not affect the response code to QUIT, which is always 221. Thus, the ACL
-does not in fact control any access. For this reason, it may only accept
+does not in fact control any access.
+For this reason, it may only accept
or warn as its final result.
This ACL can be used for tasks such as custom logging at the end of an SMTP
This option requests delivery be attempted while the item is being received.
The option is usable in the RCPT ACL.
-If enabled for a message recieved via smtp and routed to an smtp transport,
+If enabled for a message received via smtp and routed to an smtp transport,
and only one transport, interface, destination host and port combination
is used for all recipients of the message,
then the delivery connection is made while the receiving connection is open
for a mail will be quietly ignored.
If a recipient-verify callout connection is subsequently
requested in the same ACL it is held open and used for
-any subsequent receipients and the data,
+any subsequent recipients and the data,
otherwise one is made after the initial RCPT ACL completes.
Note that routers are used in verify mode,
Cutthrough delivery is not supported via transport-filters or when DKIM signing
of outgoing messages is done, because it sends data to the ultimate destination
before the entire message has been received from the source.
-It is not supported for messages recieved with the SMTP PRDR option in use.
+It is not supported for messages received with the SMTP PRDR option in use.
Should the ultimate destination system positively accept or reject the mail,
a corresponding indication is given to the source system and nothing is queued.
received, that is, in an ACL specified by &%acl_smtp_data%& or
&%acl_not_smtp%&. It checks the syntax of all header lines that can contain
lists of addresses (&'Sender:'&, &'From:'&, &'Reply-To:'&, &'To:'&, &'Cc:'&,
-and &'Bcc:'&). Unqualified addresses (local parts without domains) are
+and &'Bcc:'&), returning true if there are no problems.
+Unqualified addresses (local parts without domains) are
permitted only in locally generated messages and from hosts that match
&%sender_unqualified_hosts%& or &%recipient_unqualified_hosts%&, as
appropriate.
warn message = X-Warn: sending host is on dialups list
dnslists = dialups.mail-abuse.org
.endd
-DNS list lookups are cached by Exim for the duration of the SMTP session,
+.cindex cacheing "of dns lookup"
+.cindex DNS TTL
+DNS list lookups are cached by Exim for the duration of the SMTP session
+.new
+(but limited by the DNS return TTL value),
+.wen
so a lookup based on the IP address is done at most once for any incoming
-connection. Exim does not share information between multiple incoming
+connection (assuming long-enough TTL).
+Exim does not share information between multiple incoming
connections (but your local name server cache should be active).
accepted. It can be used in the &%acl_smtp_rcpt%&, &%acl_smtp_predata%&,
&%acl_smtp_mime%&, &%acl_smtp_data%&, or &%acl_smtp_rcpt%& ACLs. In
&%acl_smtp_rcpt%& the rate is updated one recipient at a time; in the other
-ACLs the rate is updated with the total recipient count in one go. Note that
+ACLs the rate is updated with the total (accepted) recipient count in one go. Note that
in either case the rate limiting engine will see a message with many
recipients as a large high-speed burst.
specialized interfaces for &"daemon"& type virus scanners, which are resident
in memory and thus are much faster.
-.new
A timeout of 2 minutes is applied to a scanner call (by default);
if it expires then a defer action is taken.
-.wen
.oindex "&%av_scanner%&"
You can set the &%av_scanner%& option in the main part of the configuration
The following scanner types are supported in this release:
.vlist
-.new
.vitem &%avast%&
.cindex "virus scanners" "avast"
This is the scanner daemon of Avast. It has been tested with Avast Core
-Security (currenty at version 1.1.7).
+Security (currently at version 1.1.7).
You can get a trial version at &url(http://www.avast.com) or for Linux
at &url(http://www.avast.com/linux-server-antivirus).
This scanner type takes one option,
If you use a remote host,
you need to make Exim's spool directory available to it,
as the scanner is passed a file path, not file contents.
-For information about available commands and their options you may use
+For information about available commands and their options you may use
.code
$ socat UNIX:/var/run/avast/scan.sock STDIO:
FLAGS
SENSITIVITY
PACK
.endd
-.wen
.vitem &%aveserver%&
This is a general-purpose way of talking to simple scanner daemons
running on the local machine.
There are four options:
-an address (which may be an IP addres and port, or the path of a Unix socket),
+an address (which may be an IP address and port, or the path of a Unix socket),
a commandline to send (may include a single %s which will be replaced with
the path to the mail file to be scanned),
an RE to trigger on from the returned data,
message.
The &%malware%& condition takes a right-hand argument that is expanded before
-.new
use and taken as a list, slash-separated by default.
-.wen
The first element can then be one of
.ilist
A regular expression, in which case the message is scanned for viruses. The
condition succeeds if a virus is found and its name matches the regular
expression. This allows you to take special actions on certain types of virus.
-.new
Note that &"/"& characters in the RE must be doubled due to the list-processing,
unless the separator is changed (in the usual way).
-.wen
.endlist
You can append a &`defer_ok`& element to the &%malware%& argument list to accept
messages even if there is a problem with the virus scanner.
Otherwise, such a problem causes the ACL to defer.
-.new
You can append a &`tmo=<val>`& element to the &%malware%& argument list to
specify a non-default timeout. The default is two minutes.
For example:
malware = * / defer_ok / tmo=10s
.endd
A timeout causes the ACL to defer.
-.wen
+
+.vindex "&$callout_address$&"
+When a connection is made to the scanner the expansion variable &$callout_address$&
+is set to record the actual address used.
.vindex "&$malware_name$&"
When a virus is found, the condition sets up an expansion variable called
.cindex "Rspamd"
The &%spam%& ACL condition calls SpamAssassin's &%spamd%& daemon to get a spam
score and a report for the message.
-.new
Support is also provided for Rspamd.
-For more information about installation and configuration of SpamAssassin or
+For more information about installation and configuration of SpamAssassin or
Rspamd refer to their respective websites at
&url(http://spamassassin.apache.org) and &url(http://www.rspamd.com)
-.wen
SpamAssassin can be installed with CPAN by running:
.code
nicely, however.
.oindex "&%spamd_address%&"
-By default, SpamAssassin listens on 127.0.0.1, TCP port 783 and if you
+By default, SpamAssassin listens on 127.0.0.1, TCP port 783 and if you
intend to use an instance running on the local host you do not need to set
&%spamd_address%&. If you intend to use another host or port for SpamAssassin,
you must set the &%spamd_address%& option in the global part of the Exim
spamd_address = 192.168.99.45 387
.endd
-.new
To use Rspamd (which by default listens on all local addresses
on TCP port 11333)
you should add &%variant=rspamd%& after the address/port pair, for example:
.code
spamd_address = 127.0.0.1 11333 variant=rspamd
.endd
-.wen
As of version 2.60, &%SpamAssassin%& also supports communication over UNIX
sockets. If you want to us these, supply &%spamd_address%& with an absolute
servers are tried until one succeeds. If no server responds, the &%spam%&
condition defers.
-.new
Unix and TCP socket specifications may be mixed in any order.
Each element of the list is a list itself, space-separated by default
and changeable in the usual way.
Elements after the first for Unix sockets, or second for TCP socket,
are options.
-The supported option are:
+The supported options are:
.code
pri=<priority> Selection priority
weight=<value> Selection bias
The &`pri`& option specifies a priority for the server within the list,
higher values being tried first.
-The deafult priority is 1.
+The default priority is 1.
The &`weight`& option specifies a selection bias.
Within a priority set
characters, may be omitted and will be taken as zero.
Timeout specifications for the &`retry`& and &`tmo`& options
-are the usual Exim time interval standard, eg. &`20s`& or &`1m`&.
+are the usual Exim time interval standard, e.g. &`20s`& or &`1m`&.
The &`tmo`& option specifies an overall timeout for communication.
The default value is two minutes.
The &`retry`& option specifies a time after which a single retry for
a failed connect is made.
The default is to not retry.
-.wen
The &%spamd_address%& variable is expanded before use if it starts with
a dollar sign. In this case, the expansion may return a string that is
used as the list so that multiple spamd servers can be the result of an
expansion.
+.vindex "&$callout_address$&"
+When a connection is made to the server the expansion variable &$callout_address$&
+is set to record the actual address used.
+
.section "Calling SpamAssassin from an Exim ACL" "SECID206"
Here is a simple example of the use of the &%spam%& condition in a DATA ACL:
.code
relevant if you have set up multiple SpamAssassin profiles. If you do not want
to scan using a specific profile, but rather use the SpamAssassin system-wide
default profile, you can scan for an unknown name, or simply use &"nobody"&.
-.new
Rspamd does not use this setting. However, you must put something on the
right-hand side.
-.wen
The name allows you to use per-domain or per-user antispam profiles in
principle, but this is not straightforward in practice, because a message may
have multiple recipients, not necessarily all in the same domain. Because the
-&%spam%& condition has to be called from a DATA ACL in order to be able to
+&%spam%& condition has to be called from a DATA-time ACL in order to be able to
read the contents of the message, the variables &$local_part$& and &$domain$&
are not set.
Careful enforcement of single-recipient messages
-(eg. by responding with defer in the recipient ACL for all recipients
+(e.g. by responding with defer in the recipient ACL for all recipients
after the first),
or the use of PRDR,
.cindex "PRDR" "use for per-user SpamAssassin profiles"
.cindex "spam scanning" "returned variables"
When the &%spam%& condition is run, it sets up a number of expansion
-variables. These variables are saved with the received message, thus they are
+variables.
+Except for &$spam_report$&,
+these variables are saved with the received message so are
available for use at delivery time.
.vlist
A string consisting of a number of &"+"& or &"-"& characters, representing the
integer part of the spam score value. A spam score of 4.4 would have a
&$spam_bar$& value of &"++++"&. This is useful for inclusion in warning
-headers, since MUAs can match on such strings.
+headers, since MUAs can match on such strings. The maximum length of the
+spam bar is 50 characters.
.vitem &$spam_report$&
A multiline text table, containing the full SpamAssassin report for the
message. Useful for inclusion in headers or reject messages.
+This variable is only usable in a DATA-time ACL.
-.new
.vitem &$spam_action$&
For SpamAssassin either 'reject' or 'no action' depending on the
spam score versus threshold.
For Rspamd, the recommended action.
-.wen
.endlist
This is perhaps the most important of the MIME variables. It contains a
proposed filename for an attachment, if one was found in either the
&'Content-Type:'& or &'Content-Disposition:'& headers. The filename will be
-RFC2047 decoded, but no additional sanity checks are done. If no filename was
+RFC2047
+or RFC2231
+decoded, but no additional sanity checks are done.
+ If no filename was
found, this variable contains the empty string.
.vitem &$mime_is_coverletter$&
The conditions returns true if any one of the regular expressions matches. The
&$regex_match_string$& expansion variable is then set up and contains the
matching regular expression.
+The expansion variables &$regex1$& &$regex2$& etc
+are set to any substrings captured by the regular expression.
&*Warning*&: With large messages, these conditions can be fairly
CPU-intensive.
The third item is used to introduce any text from pipe transports that is to be
returned to the sender. It is omitted if there is no such text.
.next
-.new
The fourth, fifth and sixth items will be ignored and may be empty.
The fields exist for back-compatibility
-.wen
.endlist
The default state (&%bounce_message_file%& unset) is equivalent to the
.code
log_file_path = $spool_directory/log/%slog
.endd
-If you do not specify anything at build time or run time, that is where the
-logs are written.
+If you do not specify anything at build time or run time,
+or if you unset the option at run time (i.e. &`log_file_path = `&),
+that is where the logs are written.
A log file path may also contain &`%D`& or &`%M`& if datestamped log file names
are in use &-- see section &<<SECTdatlogfil>>& below.
.cindex "log" "delivery line"
The format of the single-line entry in the main log that is written for every
delivery is shown in one of the examples below, for local and remote
-deliveries, respectively. Each example has been split into two lines in order
+deliveries, respectively. Each example has been split into multiple lines in order
to fit it on the page:
.code
2002-10-31 08:59:13 16ZCW1-0005MB-00 => marv
&` incoming_interface `& local interface on <= and => lines
&` incoming_port `& remote port on <= lines
&`*lost_incoming_connection `& as it says (includes timeouts)
+.new
+&` outgoing_interface `& local interface on => lines
+.wen
&` outgoing_port `& add remote port to => lines
&`*queue_run `& start and end queue runs
&` queue_time `& time on queue for one recipient
&`*size_reject `& rejection because too big
&`*skip_delivery `& delivery skipped in a queue run
&`*smtp_confirmation `& SMTP confirmation on => lines
-&` smtp_connection `& SMTP connections
+&` smtp_connection `& incoming SMTP connections
&` smtp_incomplete_transaction`& incomplete SMTP transactions
&` smtp_mailauth `& AUTH argument to MAIL commands
&` smtp_no_mail `& session with no MAIL commands
&` smtp_protocol_error `& SMTP protocol errors
&` smtp_syntax_error `& SMTP syntax errors
&` subject `& contents of &'Subject:'& on <= lines
-.new
&`*tls_certificate_verified `& certificate verification status
-.wen
&`*tls_cipher `& TLS cipher suite on <= and => lines
&` tls_peerdn `& TLS peer DN on <= and => lines
&` tls_sni `& TLS SNI on <= lines
&` all `& all of the above
.endd
+See also the &%slow_lookup_log%& main configuration option,
+section &<<SECID99>>&
+
More details on each of these items follows:
.ilist
&%incoming_interface%&: The interface on which a message was received is added
to the &"<="& line as an IP address in square brackets, tagged by I= and
followed by a colon and the port number. The local interface and port are also
-added to other SMTP log lines, for example &"SMTP connection from"& and to
-rejection lines
-and (despite the name) the local interface is added to &"=>"& lines..
+added to other SMTP log lines, for example &"SMTP connection from"&, to
+rejection lines, and (despite the name) to outgoing &"=>"& and &"->"& lines.
+.new
+The latter can be disabled by turning off the &%outgoing_interface%& option.
+.wen
.next
.cindex "log" "incoming remote port"
.cindex "port" "logging remote"
&%lost_incoming_connection%&: A log line is written when an incoming SMTP
connection is unexpectedly dropped.
.next
+.cindex "log" "outgoing interface"
+.cindex "log" "local interface"
+.cindex "log" "local address and port"
+.cindex "TCP/IP" "logging local address and port"
+.cindex "interface" "logging"
+.new
+&%outgoing_interface%&: If &%incoming_interface%& is turned on, then the
+interface on which a message was sent is added to delivery lines as an I= tag
+followed by IP address in square brackets. You can disable this by turning
+off the &%outgoing_interface%& option.
+.wen
+.next
.cindex "log" "outgoing remote port"
.cindex "port" "logging outgoint remote"
.cindex "TCP/IP" "logging ougtoing remote port"
&%outgoing_port%&: The remote port number is added to delivery log lines (those
-containing => tags) following the IP address. This option is not included in
-the default setting, because for most ordinary configurations, the remote port
-number is always 25 (the SMTP port).
+containing => tags) following the IP address.
+.new
+The local port is also added if &%incoming_interface%& and
+&%outgoing_interface%& are both enabled.
+.wen
+This option is not included in the default setting, because for most ordinary
+configurations, the remote port number is always 25 (the SMTP port), and the
+local port is a random ephemeral port.
.next
.cindex "log" "process ids in"
.cindex "pid (process id)" "in log lines"
.next
.cindex "log" "SMTP connections"
.cindex "SMTP" "logging connections"
-&%smtp_connection%&: A log line is written whenever an SMTP connection is
+&%smtp_connection%&: A log line is written whenever an incoming SMTP connection is
established or closed, unless the connection is from a host that matches
&%hosts_connection_nolog%&. (In contrast, &%lost_incoming_connection%& applies
only when the closure is unexpected.) This applies to connections from local
shows that the client issued QUIT straight after EHLO. If there were fewer
than 20 commands, they are all listed. If there were more than 20 commands,
the last 20 are listed, preceded by &"..."&. However, with the default
-setting of 10 for &%smtp_accep_max_nonmail%&, the connection will in any case
+setting of 10 for &%smtp_accept_max_nonmail%&, the connection will in any case
have been aborted before 20 non-mail commands are processed.
.next
&%smtp_mailauth%&: A third subfield with the authenticated sender,
The &*-C*& option is used to specify an alternate &_exim.conf_& which might
contain alternate exim configuration the queue management might be using.
-to obtain a queue listing, and then greps the output to select messages
+to obtain a queue listing, and then greps the output to select messages
that match given criteria. The following selection options are available:
.vlist
exiqgrep -f '^<>$'
.endd
.vitem &*-r*&&~<&'regex'&>
-Match a recipient address using a case-insensitve search. The field that is
+Match a recipient address using a case-insensitive search. The field that is
tested is not enclosed in angle brackets.
.vitem &*-s*&&~<&'regex'&>
If the location of a &'zcat'& command is known from the definition of
ZCAT_COMMAND in &_Local/Makefile_&, &'exigrep'& automatically passes any file
whose name ends in COMPRESS_SUFFIX through &'zcat'& as it searches it.
+If the ZCAT_COMMAND is not executable, &'exigrep'& tries to use
+autodetection of some well known compression extensions.
.section "Selecting messages by various criteria (exipick)" "SECTexipick"
.next
Serializing delivery to a specific host (when &%serialize_hosts%& is set in an
&(smtp)& transport)
+.next
+Limiting the concurrency of specific transports (when &%max_parallel%& is set
+in a transport)
.endlist
Administrators who use embedded Perl are advised to explore how Perl's
taint checking might apply to their usage.
.next
-Use of &%${expand...}%& is somewhat analagous to shell's eval builtin and
+Use of &%${expand...}%& is somewhat analogous to shell's eval builtin and
administrators are well advised to view its use with suspicion, in case (for
instance) it allows a local-part to contain embedded Exim directives.
.next
&%acl_smtp_dkim%& ACL. By default, this ACL is called once for each
syntactically(!) correct signature in the incoming message.
A missing ACL definition defaults to accept.
-If any ACL call does not acccept, the message is not accepted.
+If any ACL call does not accept, the message is not accepted.
If a cutthrough delivery was in progress for the message it is
summarily dropped (having wasted the transmission effort).
&%pass%&: The signature passed verification. It is valid.
.endlist
.vitem &%$dkim_verify_reason%&
-A string giving a litte bit more detail when &%$dkim_verify_status%& is either
+A string giving a little bit more detail when &%$dkim_verify_status%& is either
"fail" or "invalid". One of
.ilist
&%pubkey_unavailable%& (when &%$dkim_verify_status%&="invalid"): The public
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